Fluid temperature control device

ABSTRACT

A fluid temperature control device, which has a high cooling capacity, wide controllable temperature range and an excellent temperature control accuracy. A transparent cylinder ( 3 ) is inserted in a cylindrical-shaped vessel ( 1 ), and a columnar-shaped heating lamp ( 5 ) is inserted in the transparent cylinder ( 3 ). A fluid desired to be temperature controlled is made to flow in a passage ( 25 ) between the vessel ( 1 ) and the transparent cylinder ( 3 ). Joined to an outer peripheral al surface of the vessel ( 1 ) is a thermoelectric conversion element ( 7 ) , to an outer surface of which is joined a cooling pipe ( 9 ). A cooling liquid is made to flow in the cooling pipe ( 9 ) . Fluid heating is effected by the heating lamp ( 5 ). Fluid cooling is effected by the cooling liquid and the thermoelectric conversion element ( 7 ) forcibly absorbs heat from the fluid and discharges heat to the cooling liquid to thereby cool the fluid rapidly and cool the fluid to a temperature lower than that of the cooling liquid. Further, the thermoelectric conversion element ( 7 ) is used to suppress cooling by the cooling liquid and control an amount of cooling with good accuracy and good responsiveness.

TECHNICAL FIELD

The present invention relates to a fluid temperature control device, andmore particularly to an improved construction for cooling a fluid.

BACKGROUND ART

A circulating fluid is often used to control the temperature of aprocessing chamber or walls of a device, such as an constant-temperaturetank, semiconductor manufacturing device (etching device or CVD devicefor example), or plastic plate thermocompression molder. In JapanesePatent Laid-open No. 7-280470 and Japanese Patent Laid-open No. 7-308592are disclosed devices suitable for controlling the temperature of acirculating fluid.

The device disclosed in Japanese Patent Laid-open No. 7-280470 has anelectric heater inserted into a pipe in which is flowing a fluid;covering the outside surface of this pipe is an even larger pipe, andcooling water is made to flow between the outside pipe and inside pipe.The electric heater and the cooling water are used to control thetemperature of the fluid.

The device disclosed in Japanese Patent Laid-open No. 7-308592 has aradiator joined via a thermoelectric conversion element to a heattransfer block, on the inside of which is made to flow a fluid. Thefluid flowing in the block is cooled or heated by the thermoelectricconversion element. The heat absorbed by the thermoelectric conversionelement from the fluid is discharged to the atmosphere by a radiator.

The above-mentioned conventional fluid temperature control devices havethe following disadvantages, in particular as relates to coolingperformance.

The device in Japanese Patent Laid-open No. 7-280470 cannot cool thefluid below the temperature of the cooling liquid, which means it has anarrow cooling temperature range. Further, in general, it is difficultto make fine adjustments to the cooling liquid temperature or flowvolume, so if the fluid temperature is not finely adjusted by also usinga heater during cooling, then the fluid cannot be cooled to the targettemperature with good accuracy.

The device of Japanese Patent Laid-open No. 7-308592 discharges heat tothe atmosphere from a thermoelectric conversion element during cooling,but the low heat capacity of the atmosphere causes the cooling capacityto be low, which means it is difficult to process a large quantity offluid in a short time. Further, because the thermoelectric conversionelement is used for both heating and cooling, the controllabletemperature range is not very wide and the life of the thermoelectricconversion element is shortened.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a fluid temperaturecontrol device with high cooling capacity, wide controllable temperaturerange, and excellent temperature control accuracy.

An additional object of the present invention is to provide a fluidtemperature control device with simple cooling amount control.

In accordance with a first aspect of the present invention, the fluidtemperature control device comprises a fluid passage in which flows afluid, a cooling liquid passage in which flows a cooling liquid, andthermoelectric conversion elements situated between the fluid passageand the cooling liquid passage so as to allow heat to be absorbed fromthe fluid and heat to be discharged to the cooling liquid.

By placing the thermoelectric conversion elements between the fluidpassage and the cooling liquid passage to effect absorption of heat fromthe fluid and discharge of heat to the cooling liquid, the fluidtemperature control device affords larger cooling capacity thanconventional devices, which performs cooling by means of the coolingliquid alone or discharge heat from the thermoelectric conversionelements to the atmosphere, and allows the fluid to be cooled to atemperature below the temperature of the cooling liquid. Further, thethermoelectric conversion elements not only increase the amount ofcooling but can also act to suppress the amount of cooling by thecooling liquid to allow fine control of the amount of cooling, which isdifficult to achieve using just a cooling liquid.

It is desirable that the fluid temperature control device furthercomprise a heater that is placed in the proximity of the fluid passage.It is desirable that the heater be a lamp that emits infrared light.This makes it possible to effect heating and cooling of the fluid over awide temperature range.

In a preferred embodiment, there is a cylindrical vessel and along theoutside surface of this vessel are placed thermoelectric conversionelements. A transparent cylinder is inserted into the vessel, and thespace between the outside surface of the transparent cylinder and theinside surface of the vessel forms the fluid passage. Into thetransparent cylinder is inserted an infrared light emitting lamp thatacts as a heater. The thermoelectric conversion elements can be joinedto the outside surface of the vessel or can be embedded in the wall ofthe vessel. The thermoelectric conversion elements are placed oversubstantially the entire outside surface area of the vessel. On theexterior of the thermoelectric conversion elements is placed a coolingliquid passage. The cooling liquid passage can be formed by joining tothe thermoelectric conversion elements the tubes in which flows thecooling liquid, or by fitting a larger diameter outer cylinder about theexterior of the vessel so that the space between the inside surface ofthe outer cylinder and the outside surface of the vessel or the outsidesurfaces of the thermoelectric conversion elements forms a coolingliquid passage. Further, a large number of fins are placed in the fluidpassage and the cooling liquid passage.

Water or refrigerant from a refrigeration circuit can be used as thecooling liquid in the cooling liquid passage of the fluid temperaturecontrol device of the present invention. Alternatively, anti-freeze canbe cooled by a refrigeration circuit and then made to flow in thecooling liquid passage.

In accordance with a second aspect of the present invention, the fluidtemperature control device comprises a cylindrical vessel having a fluidpassage along its inner surface and thermoelectric conversion elementsplaced on the wall of the vessel for absorbing heat from the fluid.

Because the fluid temperature control device allows the thermoelectricconversion elements to be placed on the wall of the cylindrical vesselso as to surround the fluid passage, a cooling capacity that is highgiven the size of the device can be achieved, as can a wide coolingtemperature range. Further, by allowing the amount of cooling to becontrolled by the thermoelectric conversion elements while also allowingnearly uniform cooling of the fluid in the fluid passage, there isprovided high accuracy of temperature control.

It is desirable that the fluid temperature control device furthercomprise a cooling liquid passage placed in proximity to thethermoelectric conversion element in order to absorb the heat dischargedfrom the thermoelectric conversion element. This significantly increasesthe cooling capacity. Further, it is desirable that the fluidtemperature control device further comprise a heater, situated inproximity to the fluid passage, for heating the fluid.

If the wall of the cylindrical vessel is sufficiently thick, a pluralityof holes or hollows can be placed in the wall. This will reduce thevolume of the cylinder, making it lighter, and will reduce the heatcapacity of the cylinder, improving the thermal response of the device.It is desirable that the shape and position of the holes or hollows beselected such that the areas of the cylinder wall without holes orhollows will extend continuously along a heat transmission path from thevessel interior side fluid passage to the thermoelectric conversionelements. This will allow almost no degradation of the vessel's heattransmission even when there are holes or hollows in the vessel.

Other objects and features of the present invention will become apparentthrough the following description of the embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of a fluid temperature controldevice pertaining to a first embodiment of the present invention;

FIG. 2 is a cross-section arrow view drawing at line A—A shown in FIG.1;

FIG. 3 shows perspective views of fin shape variations;

FIG. 4 shows perspective views of the thermoelectric conversion element;

FIG. 5 is a transverse sectional view of a fluid temperature controldevice pertaining to a second embodiment of the present invention;

FIG. 6 is a transverse sectional view of a fluid temperature controldevice pertaining to a third embodiment of the present invention;

FIG. 7 is a transverse sectional view of a fluid temperature controldevice pertaining to a fourth embodiment of the present invention;

FIG. 8 is a transverse sectional view of a fluid temperature controldevice pertaining to a fifth embodiment of the present invention;

FIG. 9 shows transverse sectional views of several cooling tubevariations;

FIG. 10 is a transverse sectional view of a variation of thethermoelectric conversion element placement;

FIG. 11 is a perspective view of another variation of the thermoelectricconversion element placement;

FIG. 12 is a circuit diagram of a variation of an arrangement forsupplying cooling liquid to a fluid temperature control unit;

FIG. 13 is a circuit diagram of another variation of an arrangement forsupplying cooling liquid to a fluid temperature control unit;

FIG. 14 is a partially exploded and cutaway perspective view of a fluidtemperature control unit pertaining to a fifth embodiment of the presentinvention;

FIG. 15 is a transverse sectional view of a mounting area of athermoelectric conversion element of a fifth embodiment of the presentinvention;

FIG. 16 is a transverse sectional view of a variation of a mountingstructure for a thermoelectric conversion element;

FIG. 17 is a partially exploded and cutaway perspective view a fluidtemperature control unit pertaining to a sixth embodiment of the presentinvention;

FIG. 18 is a longitudinal sectional view of a variation of a vesselpertaining to a fifth and sixth embodiment of the present invention; and

FIG. 19 is a longitudinal sectional view of a variation of a vesselpertaining to a second embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The preferred embodiments of the present invention will now be describedwith reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a fluid temperature controldevice pertaining to an embodiment of the present invention; FIG. 2 is atransverse sectional view of the device seen along line A—A.

A round cylindrical transparent cylinder 3 is inserted into a vessel 1having a polygonal cylindrical shape, such as a hexagonal cylindricalshape, and is positioned concentrically to the axis of the vessel, and arod-shaped heating lamp 5 is inserted into the transparent cylinder 3and positioned concentrically to the axis of the transparent cylinder,as shown in FIGS. 1 and 2. Six long, flat thermoelectric conversionelements 7, 7, . . . are joined to the six flat sides that constitutethe outer surface of the vessel 1. Further, cooling pipes 9, 9, . . . ,which are shaped as rectangular cylinders, are joined to the outsidesurfaces of the six thermoelectric conversion elements 7, 7, . . . . Theshape of the vessel 1 is not limited to a hexagonal cylinder, but can bea square cylinder or some other polygonal cylinder.

Doughnut-shaped bushings 11, 11 are fitted about the exteriors of theportions of both ends of the transparent cylinder 3 that protrudeoutwardly at both ends of the vessel 1, and these bushings 11, 11 sealboth ends of the vessel 1 and a cooling tube 9. The joints between thebushings 11, 11 and the transparent cylinder 3 are sealed by O-rings 13,13. On the outside of each bushing 11, 1 is placed a disc-shaped bushing15, 15 that has a circular hole in the center, these bushings being heldin place by screws. The outer bushings 15, 15 hold the inner bushings11, 11 and the transparent cylinder 3 by holding them from both endswhile supporting both ends of the heating lamp 5.

In the proximity of the two ends of the vessel 1 are respectivelylocated a fluid inlet 17 that causes the fluid to flow into the vessel 1and a fluid outlet 19 that causes the fluid to flow out of the vessel 1.Further, the cooling pipes 9, 9, . . . are linked together in theproximity of both ends, and in the place where both ends are linked arelocated a cooling liquid inlet 21 for causing the cooling liquid to flowinto the cooling pipes 9, 9, . . . , and a cooling liquid outlet 23 fordischarging the cooling liquid from cooling pipes 9, 9, . . . . Separatecooling liquid inlets and outlets can be provided for each of thecooling pipes 9. The fluid that has flowed into the vessel 1 flows inthe passage (hereafter “fluid passage”) 25 between the vessel 1 and thetransparent cylinder 3 from one end of the vessel 1 to its other end.Further, the cooling liquid flows in each cooling pipe 9 in the oppositedirection of the fluid.

On the inside surface of the vessel 1 are provided a large number offins 27 (omitted from the drawing in FIG. 1). The fins 27 aredistributed at nearly the same density throughout the entire area offluid passage 25. A small gap is left between the distal ends of thefins 27 and the transparent cylinder 3, and therefore the fins 27 andthe transparent cylinder 3 do not make contact. A large number of fins29 are also provided on the interior of the wall of each cooling tube 9joined to the thermoelectric conversion elements 7 (omitted from thedrawing in FIG. 1). The fins 29 are distributed at nearly the samedensity throughout the entire area inside the cooling tube 9. A smallgap is left between the distal ends of the fins 29 and the wall on theopposite side of the cooling tube 9, therefore, the distal ends of thefins and the tube wall do not make contact.

It is desirable that the vessel 1 be made from a material with goodthermal conductivity, good corrosion resistance, and good moldabilty,such as aluminum, copper, or stainless steel. For the cooling tube 9, itis desirable that at least the wall thereof which is joined to thethermoelectric conversion element 7 be made from a material with thermalconductivity that is as good as that used for the vessel 1, but theother walls can be made from a material that does not have high thermalconductivity but that does have good corrosion resistance and goodmoldability, such as plastic, vinyl chloride, or ceramics. It isdesirable that the transparent cylinder 3 be made from a heat resistantmaterial with very high light transmission, such as quartz glass. It isdesirable that the heating lamp 5 be a type that emits much infraredlight, such as a halogen lamp for heating applications. It is desirablethat the bushings 11, 15 be made from a material with suitableelasticity and sufficient heat resistance, such as hard rubber, plastic,or metal. For the joined surfaces of the vessel 1 and eachthermoelectric conversion element 7, and the joined surfaces of eachthermoelectric conversion element 7 and each cooling pipe 9, it isdesirable that a tight contact be achieved by tightening with screwsafter applying a packing having high heat conductivity, such as silicongrease, to obtain complete adhesion between both surfaces to minimizethe contact heat resistance.

The fins 27, 29 are made from a material with high heat conductivity,good corrosion resistance, and good moldability, such as aluminum,copper, or stainless steel. Further, it is desirable that this materialalso have good infrared light absorptivity. A variety of shapes can beused for the fins 27, 29, such as those shown in FIGS. 3A through 3H.FIG. 3A shows a thin sheet bent in a cross-sectional square wave form,FIG. 3B shows a thin sheet bent in a cross-sectional triangular waveform, FIG. 3C shows a thin sheet bent in a cross-sectional wave shapethat has also been formed into a wave pattern along the ridges, and FIG.3D shows a plurality of belt-shaped thin sheets that have been bent intoa wave form and that have been placed with the wave positions beingmutually offset. FIG. 3E shows a wave-shaped thin sheet with the surfacecovered with many indentations or protrusions, and FIG. 3F shows awave-shaped thin sheet with the surface covered with many louver-likeslits. Further, FIG. 3G shows pin-like fins, and FIG. 3H shows simpleplate-shaped fins.

The arrows in FIG. 3 indicate the direction of flow (nearly parallel tothe center axis on the interior of the vessel 1) of the fluid or coolingliquid in relation to the fins when the fluid or cooling liquid pressureloss due to the fins is minimized. It is desirable that the fins beinclined at an angle that is more suitable for the arrow flow directionthan the fin attitude shown in the drawing in order to assure goodexchange of heat between the fins and the cooling liquid or fluid.

Further, in particular for the fins 27 in the vessel 1, it is desirablethat the fins 27 be oriented as follows: When using a substance with ahigh light absorptivity, such as water or ethylene glycol, as the fluid,it is desirable that the fins 27 are stood parallel to the direction ofinfrared light radiation, or, in other words, that they are stoodradially in the vessel 1, so that the infrared light from the heatinglamp 5 crosses the entire area of the fluid passage 25 and is evenlyabsorbed throughout the entire area of the fluid. However, when asubstance with a low light absorptivity, such as GALDEN (registeredtrademark) or FLUORINERT (registered trademark), is used for the fluid,it is desirable that the fins 27 be stood so as to intersect thedirection of infrared light radiation at an appropriate angle so thatthe infrared light is uniformly absorbed by all parts of the fins 27.

FIG. 4 shows the construction of the thermoelectric conversion element7.

The thermoelectric conversion element 7 has numerous small p-typesemiconductor pieces 32 and n-type semiconductor pieces 34 arrangedalternately in a two-dimensional plane, while at the same time numerousflat sheet electrodes 35 provided on top of and below the p-typesemiconductor pieces 32 and n-type semiconductor pieces 34 are used tocreate a serial electrical connection with the p-type semiconductorpieces 32 and n-type semiconductor pieces 34 arranged in alternatingorder. When direct current electricity is supplied to the thermoelectricconversion element 7, a Peltier effect is created, causing thethermoelectric conversion element 7 to absorb heat on one side thereofand to discharge heat at the other side, as shown in FIG. 4A. Thisoperation mode is hereafter called the “Peltier mode.” Further, thefaces of the thermoelectric conversion element 7 that absorb anddischarge heat are hereinafter called the “heat exchange faces.” Whenone of the heat exchange faces of the thermoelectric conversion element7 is heated and the other heat exchange face is cooled, a Seebeck effectis created, and this causes the thermoelectric conversion element 7 togenerate electricity, as shown in FIG. 4B. This operation mode ishereinafter called the “Seebeck mode.” Each of the heat exchange face ofthe thermoelectric conversion element 7 is generally covered with aninsulating plate (omitted from the drawing), such as a ceramic plate. Aswas previously explained, one heat exchange face of each thermoelectricconversion element 7 is joined to the vessel 1 and the other heatexchange face is joined to a cooling pipe 9. Each thermoelectricconversion element 7 is connected to a power supply circuit (coolingcontroller) that is not shown in the drawing.

The above arrangement causes the fluid to be 1 temperature controlled toflow into the vessel 1 via the inlet 17, through fluid passage 25, andout of outlet 19. Further, the cooling liquid is made to flow into eachcooling tube 9 from the inlet 21, through cooling tubes 9, and out ofthe outlet 23.

If the target temperature (100° C. for example) is higher than the fluidtemperature (25° C. for example) at the inlet 17, then the lamp 5 turnson. In this case, as a rule, the cooling liquid flow will be stopped andthe thermoelectric conversion element 7 will also stop operating. Thefluid will be heated by the lamp 5 exclusively. The infrared lightemitted by the lamp 5 passes through the transparent cylinder 3 andenters the fluid passage 25. If a substance with a very low lightabsorptivity (FLUORINERT for example) is used as the fluid, most of theinfrared light will be absorbed by the fins 27, with the heat then beingtransmitted from the fins 27 to the fluid. If a substance with a highdegree of light absorptivity (water or ethylene glycol, for example) isused as the fluid, the infrared light will be absorbed not only by thefins 27 but also directly by the fluid, thus heating the fluid.

The amount of heating is controlled using a temperature sensor (notshown in the drawing) placed at the outlet 19 and a heating controller(not shown in the drawing) that is connected to the temperature sensorand to the lamp 5 for adjusting the duty ratio during the time that thelamp 5 is on and the amount of light emitted. For example, the heatingcontroller controls the supply of electricity to the lamp 5 based on thedeviation between fluid outlet temperature feedback from the temperaturesensor and the target temperature. If the outlet temperature of thefluid exceeds the target temperature due to overheating or an externalfactor, the lamp 5 will be turned off. Further, if just turning off thelamp is insufficient, the cooling liquid will be made to flow and, ifnecessary, the thermoelectric conversion elements 7 will be operated.

Further, if the target temperature (30° C. for example) is below theinlet temperature of the fluid (80° C. for example), the cooling liquidwill be made to flow and the lamp 5 will normally be turned off. Theheat from the fluid will be transmitted to the cooling liquid via thefins 27, vessel 1, thermoelectric conversion elements 7, cooling tubes9, and fins 29 to cool the fluid. To rapidly cool the fluid (when theinlet temperature of the fluid has risen rapidly, for example) or tocool it below the temperature of the cooling liquid (when the targettemperature is 0° C. for example), the thermoelectric conversionelements 7 are operated in the Peltier mode to forcibly remove heat fromthe fluid and discharge it to the cooling liquid. Further, to suppresscooling by the cooling liquid (when cooling by the cooling liquid hascooled the fluid to below the target temperature, for example), thethermoelectric conversion elements 7 are operated in the Seebeck mode toconvert to electricity a portion of the heat transferred from the fluidto the cooling liquid. Using the power supply circuit to adjust thecurrent flowing in the thermoelectric conversion elements 7 in bothPeltier mode and Seebeck mode allows the amount of cooling to be finelycontrolled with good responsiveness.

As will be apparent from the foregoing description of operation, heatingis effected solely by the heat emitted from the lamp 5. The dischargedheat reaches uniformly to all areas of the fluid passage 25 that can bereached by light. This results, when the fluid is a substance thatabsorbs light, in the fluid evenly receiving the discharged heat in allareas of the fluid passage 25, raising the temperature of the fluid in asubstantially uniform manner. Further, when the fluid is a substancethat absorbs nearly no light, the large number of fins 27 that exist ata nearly uniform density throughout the entire area of the fluid passage25 evenly absorb the discharged heat and transmit it to the fluid tonearly uniformly raise the temperature of the fluid.

Most of the output from the lamp 5 is radiated as infrared light nearlyuniformly throughout the entire area of the fluid passage 25. Further,there is empty space between the lamp 5 and the transparent cylinder 3.For this reason, there is no danger that heat transmitted from the lamp5 will heat the transparent cylinder 3 to an especially hightemperature, causing it to melt, or the fluid passing in proximitythereto to boil. This allows a lamp 5 with a high output to be used,which in turn allows a high heating performance to be obtained with arelatively small device.

Cooling is conducted utilizing heat conduction and convective heattransfer from the fluid in the vessel 1 to the cooling liquid in thecooling pipes 9 via the fins 27, the thermoelectric conversion elements7, and the fins 29. Because the fins 27, 29 are positioned with nearlyuniform density throughout the entire area of the fluid passage 25 andcooling pipes 9, good cooling efficiency and little cooling temperaturenon-uniformity are achieved. Further, the thermoelectric conversionelements 7 increase the amount of cooling, expand the coolingtemperature range, and make easy control of the amount of cooling withhigh accuracy and good responsiveness, which is difficult to do withcooling liquid. Further, energy can be conserved because when in theSeebeck mode the thermoelectric conversion elements 7 convert heat fromthe fluid into electricity and return it to the power supply circuit.Using the thermoelectric conversion elements 7 to control the amount ofcooling eliminates the need to use an expensive proportional valve inorder to adjust the flow rate of the cooling water, so only aninexpensive gate valve to start and stop the cooling water flow isrequired. For the same reason, there is no need to turn on the lampduring cooling in order to prevent overcooling. Further, because thethermoelectric conversion elements 7 are used exclusively for coolingthe fluid and not for heating it, the life of the thermoelectricconversion elements 7 will be longer than they would if they were usedfor both cooling and heating.

The provision of a gap between the fins 29 inside the cooling pipes 9and the exterior wall of cooling pipes 9 has an advantage in that itmakes the arrangement resistant to being affected by the externaltemperature. Further, the gap between the fins 27 situated in the fluidpassage 25 and the transparent cylinder 3 has an advantage in that itmakes it easy to insert and remove the transparent cylinder 3 in andfrom the vessel 1 when assembling and maintaining the device.

FIG. 5 shows a transverse sectional view of a fluid temperature controldevice pertaining to a second embodiment of the present invention.

The vessel 31 is a cylinder having an interior wall that is round whenviewed in transverse section and an exterior wall that is square whenviewed in transverse section, as shown in FIG. 5, and can bemanufactured by extrusion molding of a metal, for example. The exteriorcircumference of the vessel 31 has four flat sides to which therespective thermoelectric conversion elements 7 are joined. Thearrangement of other parts is the same as the embodiment shown in FIGS.1 and 2. The fins in the fluid passage 33 and cooling pipes 9 have beenomitted from the drawing to make it easier to read the drawing. Due tothe perfectly circular cylindrical shape of the fluid passage 33, it isexpected that this embodiment will provide even less fluid temperaturenon-uniformity than the previous embodiment. The externalcross-sectional shape of the vessel 31 is not limited to a square, butcan be another polygonal shape.

FIG. 6 shows a transverse sectional view of a fluid temperature controldevice pertaining to a third embodiment of the present invention.

The vessel 41 is a round cylinder with a thick wall that has a pluralityof thermoelectric conversion elements embedded in the wall around theentire circumference of the vessel, as shown in FIG. 6. The exterior ofthe vessel 41 is enclosed by an outer cylinder 45 that has a largerdiameter, and between the outer cylinder 45 and the vessel 41 is acooling water passage 47 through which flows the cooling water. A largenumber of fins (omitted from the drawing) are placed on the inside andoutside surfaces of the vessel 41, and these fins are distributed atnearly uniform density throughout the entire area of the fluid passage43 and the cooling liquid passage 47. The arrangement of other parts isthe same as the embodiment shown in FIGS. 1 and 2. It is desirable thatthe gaps between adjacent thermoelectric conversion elements 7 be notmade of the same material as the wall of the vessel 41, as shown in thedrawing, but rather be filled with a material that has very poor heatconductivity (not shown in the drawing).

FIG. 7 shows a transverse sectional view of a fluid temperature controldevice pertaining to a fourth embodiment of the present invention.

To the outside surface of a round cylindrical vessel 51 are joined aplurality of curved thermoelectric conversion elements 57 that areclosely spaced around the entire circumference of the vessel, as shownin FIG. 7. The exterior of the vessel 51 is enclosed by a roundintermediate cylinder 55, and between the intermediate cylinder 55 andthe vessel 51 are placed thermoelectric conversion elements 57, whichare closely held between the intermediate cylinder 55 and the vessel 51.The exterior of the intermediate cylinder 55 is enclosed by a roundouter cylinder 59, and between the outer cylinder 59 and theintermediate cylinder 55 is a cooling water passage 61. It is desirablethat the gaps 58 between adjacent thermoelectric conversion elements 57be filled with a layer of air or a material that has very poor heatconductivity. The arrangement of the other parts is the same as in theembodiment shown in FIG. 6. The fins in the fluid passage 53 and in thecooling water passage 61 are omitted from the drawing.

FIG. 8 shows a transverse sectional view of a fluid temperature controldevice pertaining to a fifth embodiment of the present invention.

To the outside surface of a round cylindrical vessel 51 are joined aplurality of curved thermoelectric conversion elements 63, and theexterior of this arrangement is enclosed by an outer cylinder 59, acooling liquid passage 65 being formed between the outer cylinder 59 andthe thermoelectric conversion elements 63, as shown in FIG. 8. Theexterior faces of the thermoelectric conversion elements 63, especiallythe side faces, are sealed with a suitable sealant 64 so that coolingliquid does not seep into the elements. Further, the heat exchange facesof the thermoelectric conversion elements 63 facing the cooling liquidpassage 65 are provided with fins 67. The thermoelectric conversionelements 63 and the fins 67 can be formed as a single unit. The otherparts of the arrangement are the same as the embodiment shown in FIG. 7.The fins in the fluid passage 53 are omitted from the drawing.

FIGS. 9A to 9C show transverse sections of several cooling pipevariations.

The cooling pipe 71 shown in FIG. 9A can be extrusion molded, forexample, in such a way that a plurality of cooling liquid passages 73are formed on the inside of the cooling tube 71, and is joined the heatexchange face of a thermoelectric element 7. Dividers 75 between thecooling liquid passages 73 act as fins, so there is no particular needto provide fins. The cooling pipe 81 shown in FIG. 9B has a plurality ofinterior cooling liquid passages 83 that are formed, for example, bycasting copper pipes 83 in an aluminum block 85, and joining the elementto the heat exchange face of a thermoelectric conversion element 7. Thisarrangement also does not require that fins be provided. The coolingtube 91 shown in FIG. 9C is formed, for example, by casting a singlecopper pipe 93 in an aluminum block 95, and joining the element to theheat exchange face of a thermoelectric conversion element 7.

FIG. 10 shows a variation of the mode of joining the thermoelectricconversion element to the vessel (all elements other than thethermoelectric conversion elements and vessel are omitted from thedrawing).

Thermoelectric conversion elements 103 are joined to three of the sixflat sides on the exterior of hexagonal vessel 101, for example, placingthem on every other side as shown in FIG. 10. Thus, the thermoelectricconversion elements 103 do not need to cover absolutely the entireexternal area of the vessel 101, provided they are placed so as touniformly cool the fluid that flows through the vessel 103 (in otherwords, if the thermoelectric conversion elements 103 are placed oversubstantially the entire outer surface).

FIG. 11 shows another variation of the mode of joining thethermoelectric conversion elements to a vessel.

FIG. 11 shows several thermoelectric conversion belts 115, each composedof four thermoelectric conversion elements 113 connected in a loop andfitted about a square cylindrical vessel 111, for example. Thethermoelectric conversion belts 115 can be placed against each other orseparated, as shown in the drawing, if satisfactory cooling effect canbe obtained. The cooling pipes are not shown in the drawing, but can beextended parallel to the center axis of the vessel 111 or wound in aspiral around the outside of the vessel 111 so as to firmly contact theoutside faces of the thermoelectric conversion belts 115. If athermoelectric conversion element 113 fails, the thermoelectricconversion belt 115 can be replaced as a unit.

FIG. 12 shows a variation of an arrangement for supplying cooling liquidto the fluid temperature control device of the present invention.

A fluid temperature control device 121 of the present invention isconnected to a refrigeration circuit 123 that uses a refrigerant, suchas a CFC, as shown in FIG. 12. In the refrigeration circuit 123, therefrigerant is abiabatically compressed by a compressor 125 and is thencooled and condensed by cooling water 129 in a condenser 127; after thenbeing brought to low pressure by an expansion valve 131, the refrigerantis sent to the cooling pipes 133 of the fluid temperature control device121, which acts as an evaporator, and here a fluid 135 that flowsthrough the fluid temperature control device 121 is cooled. Thisarrangement allows the fluid to be cooled to a lower temperature thanwhen the cooling water is allowed to flow unmodified into the coolingpipes 133 of the fluid temperature control device 121. In other words,where cooling water (normally about 25° C.) flows into the cooling pipes133 and the action of the thermoelectric conversion elements has cooledthe fluid to about 0° C., for example, then the arrangement shown inFIG. 12 can cool the fluid to minus several tens of degrees Celsiusthrough the action of the refrigeration circuit and of thethermoelectric conversion elements. FIG. 12 only shows one fluidtemperature control device 121, but a plurality of fluid temperaturecontrol devices 121 can be connected to a single refrigeration circuit123.

FIG. 13 shows another variation of an arrangement for supplying coolingliquid.

An anti-freeze circuit 137 is additionally provided between the samerefrigeration circuit 123 and fluid temperature control device 121 thatare shown in FIG. 12. The anti-freeze circuit 137 circulates anti-freezebetween the evaporator 135 of the refrigeration circuit 123 and thecooling pipes 133 of the fluid temperature control device 121 using apump 139. This arrangement achieves the same cooling capacity as thearrangement shown in FIG. 12, but because there is no need to extend arefrigeration pipe (the interior is in a near vacuum state) from theexpansion valve 131 to inside the fluid temperature control device 121,the design of the fluid temperature control device 121 is simpler thanthat of the device shown in FIG. 12. FIG. 13 shows only one fluidtemperature control device 121, but a plurality of fluid temperaturecontrol devices 121 can be connected to a single refrigeration circuit137.

FIG. 14 shows a sixth embodiment.

The vessel 201 has an approximately square pillar shape, and on each ofthe four exterior faces of this pillar is formed a trough 203 that runsthe length of the vessel 201. The cross-sectional shape of each trough203 is rectangular, and in these troughs are embedded a large number offlat thermoelectric conversion elements 205 that are of a size to justfit into these troughs. Covering the troughs 203 from the outside arefour long, narrow cooling plates 207 held in place over the fourexterior sides of the vessel 201 by screws 209. Each cooling plate 207has an interior cooling liquid passage 211 that runs the length of thecooling plate, and in each cooling liquid passage 211 are provided fins(omitted from the drawing), which are similar to those already explainedin other embodiments. Further, the two lengthwise ends of each coolingplate 207 are respectively provided with a cooling liquid inlet pipe 213that leads the cooling liquid to the passage 211 and a cooling liquidoutlet pipe 215 that discharges the cooling liquid from the passage 211.

In the center of the vessel 201 is formed a round cylindrical hollowthat runs the length of the vessel 201. In the round cylindrical hollowis inserted a set consisting of a heating lamp 5 and a transparentcylinder 3 that are the same as those already explained in otherembodiments, thereby forming a fluid passage 217 between the outsidesurface of the transparent cylinder 3 and the inside surface of thehollow. In the fluid passage 217 are provided fins 219 joined to theinside surface of the hollow.

The central portion of each end of the vessel 201 is covered with aring-shaped cap 221 so that each end of the fluid passage 217 is sealed.Both ends of lamp 5 pass through the ring-shaped caps 221 and extend tothe outside. Further, the cap 221 closest to the cooling liquid inlettube 213 is provided with a fluid outlet pipe 223 for discharging thefluid from the fluid passage 217, and the other cap, which is hidden bythe vessel 201 and therefore, is not shown in the drawing, is providedwith a fluid inlet pipe f or allowing fluid to enter the fluid passage217. Therefore, the fluid in the fluid passage 217 flows in the oppositedirection of the cooling liquid in the cooling liquid passage 211.Further, an approximately square end plate 225 that has a hole in thecenter for the cap 221 to pass through is secured, via a rubber packing227 of the same shape interposed between it and the vessel 210, to eachend of the vessel 201 by means of machine screws. Both ends of thecooling liquid passage 211 are covered by the end plates 225.

FIG. 15 shows a cross-section of the thermoelectric conversion element205 mounting on the device shown in FIG. 14.

As shown in the drawing, tightened screws 209 hold the front and backheat exchange faces 205 a, 205 b of the thermoelectric conversionelement 205 securely against the bottom 203 a of the trough 203 and theoutside face 207 a of the cooling plate 207, respectively (siliconegrease, etc., is spread on the mated surfaces) to minimize heatresistance at the mated surfaces. In FIG. 15, there are shown gapsbetween the side faces of the thermoelectric conversion element 205 andthe interior side faces of the trough 203, but the two elements cantouch leaving no gap. It is also possible to not provide a trough in thevessel 201, but to simply sandwich the thermoelectric conversion unit205 between the vessel 201 and the cooling plate 207 and secure it inplace with screws 209, as shown in FIG. 16.

FIG. 17 shows a seventh embodiment.

In this device the inside arrangement of the cooling plates of thedevice shown in FIG. 14 has been changed. In other words, on the insideof each cooling plate 231 are embedded a plurality of thin coolingliquid pipes 233 that run parallel to each other along the length of thecooling plate. The plurality of cooling liquid pipes 233 are connectedto a single cooling liquid inlet pipe 235 on one end and to a singlecooling liquid outlet pipe 237 on the other end. The cooling liquidinlet pipe 235 and cooling liquid outlet pipe 237 each extend from aside face of a cooling plate 231 and pass to the outside through thepacking 227 and the end plate 225.

FIG. 18 shows a variation of the cross-sectional construction of thevessel in the devices shown in FIGS. 14 and 17.

The wall of the vessel 201 shown in FIGS. 14 and 17 is of considerablethickness, and in this case a large number of holes (or hollows) 241 canbe provided in the 13 wall of the vessel 201, as shown in FIG. 18. It isdesirable that holes 241 be formed so that portions of the vessel wallwithout holes 241 extend continuously from the interior to the exteriorof the vessel (in other words, in the radial direction) to ensure goodconduction of heat from the fluid passage 217 in the vessel to thethermoelectric conversion elements 205 situated on the exterior of thevessel. Using a length-wise extrusion molding method to manufacture thevessel 201 is a simple way to manufacture a vessel 201 having many holes241 running its length. The presence of a large number of holes 241reduces the volume of the vessel 201 to make it lighter and lessexpensive, and the accompanying reduction of the heat capacity of thevessel 201 gives the device good thermal responsiveness. Similar holescan also be formed in the vessel wall in the other embodiments. Forexample, the embodiment shown in FIG. 5 can also be made lighter inweight and given improved thermal responsiveness by forming holes 241 inthe thick areas of the wall of vessel 31 as shown in FIG. 19.

The preceding description of the embodiments intended to facilitate anunderstanding of the present invention, and these embodiments are notintended to limit the scope of the present invention. The presentinvention encompasses a variety of other aspects, such as alterations,modifications, and improvements, to the above embodiments withoutdeviating from the spirit thereof. For example, without deviating fromthe spirit of the present invention, the present invention can embody afluid temperature control device the purpose of which is only to cool afluid without having means for heating the fluid, or a fluid temperaturecontrol unit that does not use a cooling liquid.

What is claimed is:
 1. A fluid temperature control device forcontrolling the temperature of a fluid, comprising: a cylindrical vesselhaving an inside surface in which is formed a fluid passage in whichflows said fluid, and having an outside surface with flat side portions;a transparent cylinder that is inserted into said vessel and that formssaid fluid passage between the inside surface of said vessel and outsidesurface of said transparent cylinder; a lamp arranged within saidtransparent cylinder and utilized as a heater for emitting infraredlight inside said fluid passage; thermoelectric conversion elementshaving first and second faces that absorb heat and discharge heat,respectively, and being attached to said flat side portions of saidoutside surface via said first face; and a cooling liquid passage inwhich flows a cooling liquid and which is joined to said second face ofsaid thermoelectric conversion elements.
 2. The fluid temperaturecontrol device according to claim 1, wherein a plurality of saidthermoelectric conversion elements are arranged over substantially theentire area of the outside surface of said vessel.
 3. The fluidtemperature control device according to claim 1, further comprising alarge number of fins that are attached to the inside surface of saidvessel and are placed in a dispersed manner within said fluid passage.4. The fluid temperature control device according to claim 1, furthercomprising a large number of fins that are placed in a dispersed mannerwithin said cooling liquid passage.
 5. The fluid temperature controldevice according to claim 1, further comprising a refrigeration circuitthat is connected to said cooling liquid passage and that has anexpansion valve through which a refrigerant passes, the refrigerantdischarged from said expansion valve being supplied as said coolingliquid to said cooling liquid passage.
 6. The fluid temperature controldevice according to claim 1, comprising: an anti-freeze circuit that isconnected to said cooling liquid passage and that supplies anti-freezeas said cooling liquid to said cooling liquid circuit; and arefrigeration circuit that is connected to said anti-freeze circuit andthat has an expansion valve through which passes a refrigerant, saidanti-freeze being cooled using the refrigerant discharged from saidexpansion valve.
 7. The fluid temperature control device according toclaim 1, wherein said vessel has troughs on the outside surface thereof,said flat side portions being formed within these troughs, and saidthermoelectric conversion elements being embedded within said troughs.8. The fluid temperature control device according to claim 7, whereinsaid fluid passage within said vessel is formed with a round cylindricalshape.
 9. The fluid temperature control device according to claim 1,wherein the wall of said vessel has holes or hollows.
 10. The fluidtemperature control device according to claim 1, wherein said vessel isformed as a polygonal cylinder, the outside surface thereof having aplurality of said flat side portions.
 11. The fluid temperature controldevice according to claim 10, wherein said fluid passage within saidvessel is formed with a round cylindrical shape.
 12. The fluidtemperature control device according to claim 1, wherein said fluidpassage within said vessel is formed with a round cylindrical shape. 13.The fluid temperature control device according to claim 1, wherein saidplurality of thermoelectric conversion elements are arranged in theaxial direction of said vessel.
 14. The fluid temperature control deviceaccording to claim 1, where said plurality of thermoelectric conversionelements are arranged in the circumferential direction of said vessel.15. A fluid temperature control device for controlling the temperatureof a fluid, comprising: a cylindrical vessel having an outside surfaceand an inside surface in which is formed a fluid passage in which flowssaid fluid; thermoelectric conversion elements having first and secondfaces that absorb heat and discharge heat, respectively, and beingattached to said outside surface via said first face; a cooling liquidpassage in which flows a cooling liquid, joined to said second face ofsaid thermoelectric conversion elements; a transparent cylinder which isinserted into said vessel and which forms said fluid passage between theinside surface of said vessel and an outside surface of said transparentcylinder; and a lamp arranged within said transparent cylinder andutilized as a heater for emitting infrared light inside said fluidpassage.
 16. The fluid temperature control device according to claim 15,wherein a plurality of said thermoelectric conversion elements arearranged over substantially the entire area of the outside surface ofsaid vessel.
 17. The fluid temperature control device according to claim15, further comprising a large number of fins that are attached to theinside surface of said vessel and are placed in a dispersed mannerwithin said fluid passage.
 18. The fluid temperature control deviceaccording to claim 15, further comprising a large number of fins thatare placed in a dispersed manner within said cooling liquid passage. 19.The fluid temperature control device according to claim 15, furthercomprising a refrigeration circuit that is connected to said coolingliquid passage and that has an expansion valve through which arefrigerant passes, the refrigerant discharged from said expansion valvebeing supplied as said cooling liquid to said cooling liquid passage.20. The fluid temperature control device according to claim 15,comprising: an anti-freeze circuit that is connected to said coolingliquid passage and that supplies anti-freeze as said cooling liquid tosaid cooling liquid circuit; and a refrigeration circuit that isconnected to said anti-freeze circuit and that has an expansion valvethrough which passes a refrigerant, said anti-freeze being cooled usingthe refrigerant discharged from said expansion valve.
 21. The fluidtemperature control device according to claim 15, wherein the wall ofsaid vessel has holes or hollows.
 22. The fluid temperature controldevice according to claim 15, wherein said fluid passage within saidvessel is formed with a round cylindrical shape.